A method of recovery of benzoic acid and crude terephthalic acid from PTA oxidation residua
Technical field
The present invention relates to solid waste resource comprehensive utilizations to utilize technical field, and in particular to a kind of from PTA oxidation residua
The method of middle recovery of benzoic acid and crude terephthalic acid.
Background technique
P-phthalic acid (PTA) is important one of large Organic Ingredients, is widely used in chemical fibre, light industry, electricity
The every field of the national economy such as son, building, while the application of PTA is also concentrated mainly on polyethylene terephthalate (letter
Claim polyester, PET), poly terephthalic acid 1,4-butanediol ester (PBT) and poly terephthalic acid 1,3-PD ester (PTT) etc. are poly-
The production of ester product.According to statistics, the PTA in 90% or more the whole world is used for the production of PET.It can be seen that the downstream extension product of PTA
Mainly polyester fiber, and PTA and 0.33-0.34 tons of the MEG (ethylene glycol) that 1 ton of PET needs 0.85 ~ 0.86 ton is produced, institute
With with the development of polyester industrial, the demand of PTA is increasing.
PTA oxidation residua be in PTA production process, due to terephthalic acid (TPA) occur in oxidation process disproportionation, decarboxylation,
Impurity caused by the side reactions such as rearrangement, non-complete oxidation, mainly there is benzoic acid, terephthalic acid (TPA), p-methylbenzoic acid, Co2+、
Mn2+, Br-, Ac- etc..
PTA oxidation residua is khaki or orange-yellow powder, is pureed solid when aqueous more, has denseer irritation
Smell, composition is unstable, changes with the accidentalia and failure that occur in production process, therefore more difficult development and utilization.
According to investigation, 300,000 tons/year of PTA process units will generate 3 kiloton of PTA oxidation residua and pureed solid or so every year, although
Residue ingredient is not quite similar, but generally speaking, in oxidation residua and pureed solid about contains 40% ~ 50% solid phase benzene carboxylic
Acid, 2% Co2+, 2.5% Mn2+, 3% Br-, wherein the solid phase benzene carboxylic acid of recoverable is about 1200 tons, recyclable Co
(Ac)2With Mn (Ac)2240 tons of mixed catalyst.For Fujian Province, such as the good dragon petrochemical industry Fang Xian Co., Ltd of private enterprise stone lion
600,000 tons/year of PTA production capacity, 1,500,000 tons/year of PTA production capacity of Xiamen Xianglu Petrochemicals Co., Ltd., Taiwan-owned enterprise, Jin Liangjia enterprise
Generated PTA oxidation residua, just there is as many as 2.1 ten thousand tons every year.And the whole nation has type of industry 19, can be deduced according to production capacity
National annual PTA oxidation residua discharge amount up to 150,000 tons, not only pollute environment and also add production by the discharge of these solid waste
Unit consumption, if therefore can these good residues of comprehensive reutilization, be greatly improved the economic benefit and competitive strength of enterprise.
In conclusion the useful composition in comprehensive reutilization PTA oxidation residua is extremely necessary.PTA is aoxidized
Residue, the method that foreign countries generally use burning are handled, and the country also has a small number of enterprises to handle using incineration method, such as Nanjing Yangzi
Petro-chemical corporation has passed through the technical appraisement for burning PTA oxidation residua;Chinese patent CN 1356183A " p-phthalic acid (PTA)
Process for burning residual dregs " also disclose that a kind of processing method of PTA burning residual dregs, this method are according to PTA residue water content size
Material is carried out dehydrating, water content is allowed to lower than 60%, then is allowed to be fused by heating equipment by dewatered material
Pasty material, then pasty material is ejected into incinerator and is burned.Although the organic matter in PTA residue can be made full use of
The thermal energy that generates burn to replace part of fuel, reduces plant energy consumption, simplifies the processing of PTA oxidation residua, prevent PTA residue pair
The pollution in soil and groundwater source.But the shortcoming of this processing mode has: 40 ~ 50% are in first, PTA oxidation residua
Benzoic acids and terephthaldehyde's acids compound can only serve as fuel in burning process, not be fully used, cause resource
Waste;In second, PTA oxidation residua be mainly mixture containing aromatic hydrocarbons, easily lead to burn it is insufficient, to cause big compression ring
Border pollution, is unfavorable for the protection of environment.Therefore, the burning disposal of residue is one and does not meet environmental-friendly way, Wo Menying
This effectively comprehensively utilizes PTA oxidation residua, turns waste into wealth, this undoubtedly has more positive social effect.
Summary of the invention
The present invention provides the method for a kind of recovery of benzoic acid and crude terephthalic acid from PTA oxidation residua, can be effective
Solve the problems, such as that solid waste resource comprehensive utilization utilizes.It is well known that recycling Co2+And Mn2+PTA oxidation residua composition afterwards
By a relatively simple, main component is benzoic acid and crude terephthalic acid, so the present invention is with the PTA process units of certain company
The oxidation residua of discharge recycles Co through pre-treatment2+And Mn2+And remove a small amount of Fe2+PTA oxidation residua afterwards is raw material, using heat
Water dissolution, cooling crystallization method recovery of benzoic acid, it is residual with the method recycling PTA oxidation for adding alkali soluble solution, oxidative decoloration, acid adding to be precipitated
Crude terephthalic acid in slag, crude terephthalic acid can directly return to the reduction process of PTA production, and benzoic acid is used as industrial antisepsis
" three win " of environmental benefit, economic benefit and social benefit is realized in agent.
Technical solution of the present invention is taken, and specific step is as follows:
Step is (1): the PTA oxidation residua in the present invention is that Co is recycled in pre-treatment2+And Mn2+Resulting PTA oxidation residua afterwards.
Step is (2): step (1) treated PTA oxidation residua being mixed in a certain ratio with water, is stirred at a certain temperature
Certain time filters while hot, obtains hot filter filter cake, and white depositions are filtered to obtain in filtrate cooling and standings after a certain period of time.
Step is (3): will through step, (2) treated that white depositions recrystallize at a certain temperature, filter, it is dry,
It is benzoic acid product after crushing.
Step is (4): certain density NaOH solution is added in through step (2) treated heat filter filter cake, adjusts pH to 8.0
~10.0, filtering.
Step is (5): a certain amount of active carbon and H is added in through step (4) treated filtrate2O2, fill at a certain temperature
Divide stirring certain time, filters while hot.
Step is (6): certain density H is added in through step (5) treated filtrate2SO4Solution adjusts its pH value to 2.0
~ 3.0, white flock precipitate is precipitated in placement after a certain period of time, filters, and washs, dry, obtains crude terephthalic acid product.
(1) the middle acetum that is added carries out impregnating recycling Co the content of present invention step2+And Mn2+And remove a small amount of Fe2+Before
Processing.
(2) water is added in the content of present invention step amount is 100 % ~ 400%;Heating temperature is 95 ~ 98 DEG C;Mixing time is
0.5~3 h;Time of repose is 0.5 ~ 2 h.
(3) the middle solution temperature recrystallized is controlled at 95 ~ 98 DEG C the content of present invention step.
The content of present invention step (4) in NaOH solution concentration be 5% ~ 20%.
(5) the middle quality that active carbon is added is 1% ~ 10% to the content of present invention step;H is added2O2Quality be 1% ~ 5%;H2O2
Concentration be 10% ~ 30%;Heating temperature is 50 ~ 70 DEG C;Mixing time is 0.5 ~ 3 h.
The content of present invention step is (6) middle to be added H2SO4The concentration of solution is 1% ~ 10%;Standing time is 1 ~ 4 h.
It can be seen from the above technical proposal that since the present invention is by carrying out plus water the PTA oxidation residua after pre-treatment
The method recovery of benzoic acid and thick terephthaldehyde that heating for dissolving, crystallisation by cooling, filter cake add alkali soluble solution, oxidative decoloration, acid adding to be precipitated
Acid, technical process is simple and clear, and easily operated.Containing using determined by ultraviolet spectrophotometry product benzoic acid in the present invention
Amount, is attained by 98.5% or more;The same content for using determined by ultraviolet spectrophotometry crude terephthalic acid, is attained by
85.0% or more.Advantage for present invention is: (1) process equipment is simple, is easy to be mass produced;(2) raw material sources are rich
Richness, it is cheap.(3) the reduction process that the crude terephthalic acid that the present invention recycles can directly return to PTA production uses, recycling
Benzoic acid can be used as industrial preservative, sufficiently and reasonably be utilized this waste solid waste resource of PTA oxidation residua, change give up into
Treasured realizes " three win " of environmental benefit, economic benefit and social benefit.
Specific embodiment
The present invention provides the method for a kind of recovery of benzoic acid and crude terephthalic acid from PTA oxidation residua, can be effective
Solve the problems, such as that solid waste resource comprehensive utilization utilizes.It is several specific embodiments of the invention below, further illustrates this
Invention, but the present invention is not limited only to this.
Embodiment one:
10 kg recycle Co2+And Mn2+30 kg water are added in PTA oxidation residua afterwards, 1 h are stirred at 98 DEG C, while hot mistake
Filter obtains hot filter filter cake, white depositions is obtained by filtration after 1 h of the cooling placement of filtrate.White depositions are carried out to weight at 95 DEG C
Crystallization, filtering are benzoic acid product (yield 25.3%, content >=98.6%) after dry, pulverize.It is added into heat filter filter cake
20% NaOH solution filters after adjusting pH to 8.0.15% H of 360 g active carbons and 100 ml is added in filtrate2O2, 50
3 h are stirred at DEG C, are filtered while hot.The H of 5 % is added in filtrate2SO4Solution adjusts its pH value to 3.0, filters after placing 2 h,
Filter cake is washed, dry, i.e. crude terephthalic acid product (yield 15.0%, content >=85.4%).
Embodiment two:
10 kg recycle Co2+And Mn2+25 kg water are added in PTA oxidation residua afterwards, 1.5 h are stirred at 96 DEG C, while hot
Filtering obtains hot filter filter cake, white depositions is obtained by filtration after 2 h of the cooling placement of filtrate.White depositions are carried out at 96 DEG C
Recrystallization, filtering are benzoic acid product (yield 24.5%, content >=98.6%) after dry, pulverize.It is added into heat filter filter cake
15% NaOH solution filters after adjusting pH to 9.0.10% H of 300 g active carbons and 200 ml is added in filtrate2O2, 60
2 h are stirred at DEG C, are filtered while hot.The H of 7 % is added in filtrate2SO4Solution adjusts its pH value to 2.5, places mistake after 1.5 h
Filter, filter cake is washed, dry, i.e. crude terephthalic acid product (yield 15.9%, content >=86.0%).
Embodiment three:
10 kg recycle Co2+And Mn2+40 kg water are added in PTA oxidation residua afterwards, 2 h are stirred at 95 DEG C, while hot mistake
Filter obtains hot filter filter cake, white depositions is obtained by filtration after 1 h of the cooling placement of filtrate.White depositions are carried out to weight at 98 DEG C
Crystallization, filtering are benzoic acid product (yield 24.2%, content >=98.5%) after dry, pulverize.It is added into heat filter filter cake
10% NaOH solution filters after adjusting pH to 8.0.30% H of 400 g active carbons and 150 ml is added in filtrate2O2, 70
1 h is stirred at DEG C, is filtered while hot.10% H is added in filtrate2SO4Solution adjusts its pH value to 2.0, filters after placing 1 h,
Filter cake is washed, dry, i.e. crude terephthalic acid product (yield 15.2%, content >=85.5%).